Exparel for Total Shoulder Arthroplasty: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Exparel for Total Shoulder Arthroplasty (NCT04364867), a randomized phase 4 study. The primary outcome is Pain Score in the 24 Hours After Surgery.

2. Clinical Question

The study also set out to examine pain at later time points, morphine use, return of functional use of the involved arm, and costs. The posted outcome results include pain scores at 48 and 72 hours and cumulative morphine milligram equivalents at 24, 48, and 72 hours. Results for return of function and cost savings are not reported in the registry record.

The primary comparison is between two postoperative pain-control approaches in a randomized, parallel-group trial. It is not a comparison of either approach with no pain treatment. The posted results describe group averages and a mean difference, so they address the average score in each group rather than the experience of every participant. The record does not provide individual-level results or details that would show how pain varied among particular participants.

3. Trial Design

This was a randomized, parallel-group Phase 4 trial with no masking, according to the registry record. The listed sponsor is Norton Healthcare. The trial is marked completed, with enrollment of 102. The record lists a start date of 2020-08-12 and a primary completion date of 2021-02-08.

Participants were assigned to Exparel or a pain pump. The Exparel arm received a single-shot injection, while the pain-pump arm received an interscalene block followed by a pump. The posted record describes the pump as being attached in the Post Anesthesia Care Unit and continuing to infuse at 4cc/hr until it runs out. Since the trial was unmasked, participants and study personnel were not described as blinded to treatment assignment. Further details about the randomization procedure, allocation concealment, or who generated assignments are not reported in the registry record.

The registry summary gives a sample-size rationale. It says prior studies of anesthetics for total shoulder arthroplasty found a mean worst pain score of 5.4 in the 24 hours after surgery on a 0 to 10 scale. The stated design aimed to detect a change of 2 points, using alpha of 0.05 and beta of 0.80, with 51 subjects in each group; the summary says 60 subjects in each arm would be enrolled to account for drop-outs. Those are design statements in the summary, not the number of participants represented in the posted primary outcome results.

The posted primary outcome has 19 participants in the Exparel group and 35 in the pain-pump group. The record does not explain why these outcome counts are smaller than the overall enrollment or why the counts differ between groups. It also does not report a participant flow account, exclusions from the analysis, or reasons for missing outcome data. Those gaps limit what can be inferred about how the posted outcome groups relate to everyone enrolled.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Pain Score in the 24 Hours After Surgery, measured over 24 hours after surgery.

The primary endpoint is the worst pain score during the 24 hours after surgery. It is recorded as a score on a scale from 0, meaning no pain, to 10, meaning the worst possible pain. The registry specifies a mean and standard deviation for this continuous measure. The central comparison is therefore between the average worst pain score in the Exparel group and the average in the pain-pump group during the stated period.

Worst pain is one way to summarize a participant’s reported pain experience over a defined postoperative interval. Using a numeric scale makes it possible to summarize responses across participants and compare group averages. The endpoint is tied to the study’s primary objective, which asks whether the two approaches differ in pain scores at 24, 48, and 72 hours; the 24-hour measure is designated as primary.

A group mean does not describe the full distribution of scores or show how many participants reported any particular level of pain. The standard deviation gives information about spread around the mean, but it does not substitute for participant-level data. The record does not report additional details about how often pain was assessed during the 24-hour period, how a participant’s worst score was collected, or how missing responses were handled.

The scale is bounded, and its values represent reported scores rather than a direct measurement of a physical quantity. The comparison should therefore be read as a difference in average scores on this specified scale, not as a change in the proportion of participants with a particular clinical experience. No threshold for interpreting the size of a score difference is reported in the registry record.

7. Results Posted in the Registry

• Pain Pump: mean 3.37 versus 0.76 on control; difference 2.61 (95% CI 1.57 to 3.65), standardized effect d = 1.10; z-test p = <0.001.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Pain Score in the 48 Hours After Surgery

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Pain Pump: mean 4.70 versus 2.53 on control; difference 2.17 (95% CI 0.92 to 3.42), standardized effect d = 0.79; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Pain Pump than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Cumulative Morphine Milligram Equivalents at 24 Hours

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Pain Pump: mean 3.57 versus 4.58 on control; difference -1.01 (95% CI -4.21 to 2.19), standardized effect d = -0.20; z-test p = 0.536.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Pain Pump and the control. The interval gives the range of effects that remain compatible with the data.

Cumulative Morphine Milligram Equivalents at 48 Hours

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Pain Pump: mean 4.19 versus 4.58 on control; difference -0.39 (95% CI -0.85 to 0.07), standardized effect d = -0.50; z-test p = 0.098.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Pain Pump and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes extend the primary question in two directions: pain scores are also reported at later postoperative time points, and cumulative morphine milligram equivalents are reported at 24 and 48 hours. The registry lists a further morphine-use outcome at 72 hours and pain at 72 hours; the posted outcomes include the pain score at 72 hours, while the posted secondary comparison details include morphine use at 24 and 48 hours. These measures address related but distinct aspects of postoperative recovery, and they should not be treated as interchangeable with the primary pain score.

Across the posted summaries, the later pain-score comparison follows the direction of the primary result, whereas the morphine-use estimates are less decisive in their uncertainty. This broad pattern does not show that pain scores and medication use must move together. They measure different outcomes, and the record does not report analyses of the relationship between a participant’s pain score and morphine use.

The secondary results add context to the primary comparison, but they do not replace it. Each outcome has its own measurement scale, time point, estimate, and uncertainty. The tables and plots present those endpoint-specific values; they should be consulted rather than collapsing the results into a single summary claim. The registry record does not report findings for the planned return of functional use of the involved arm or cost savings, so these stated secondary objectives cannot be evaluated from the posted results.

Unadjusted secondary results carry less weight because several outcomes and time points create opportunities for chance findings when each comparison is considered separately. In general, a prespecified multiplicity strategy can help control how evidence is interpreted across many tests. The registry record does not report such a strategy, a formal testing hierarchy, or reported analysis entries for the secondary outcomes. This does not invalidate the descriptive values; it means their inferential status is less clearly specified than the designated primary endpoint.

Secondary findings are most useful as a set of supporting descriptions that show whether the observed pattern is similar across related measures. They are not independent confirmation simply because they concern different times or outcomes. The record does not report a combined analysis, and the available summaries do not establish a single overall effect across pain and morphine-use measures.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Pain Score in the 48 Hours After Surgery
• Cumulative Morphine Milligram Equivalents at 24 Hours
• Cumulative Morphine Milligram Equivalents at 48 Hours
• Cumulative Morphine Milligram Equivalents at 72 Hours
• Pain Score in the 72 Hours After Surgery

9. Statistical Interpretation

10. Statistical Methods Explained

The primary endpoint is continuous: it is a numeric pain score summarized with a mean and standard deviation. The posted group means are 0.76 for Exparel and 3.37 for the pain pump. The mean difference is stated in the direction pain pump minus Exparel, giving 2.61. Direction is important: a positive estimate means the posted mean was higher in the pain-pump group on this scale. It is a difference between group averages, not an individual participant’s change from before to after surgery.

What does a mean difference summarize?

In general, a mean difference expresses how far apart two group averages are on the original measurement scale. It preserves the scale’s units, which are points on the pain scale. The calculation does not show whether all participants in one group had higher scores than all participants in the other group. The two groups can have overlapping score distributions even when their means differ. The registry reports standard deviations to describe variation within each group, but does not provide participant-level scores or a distributional plot in the record.

The reported standard deviations are 0.97 for Exparel and 2.86 for the pain pump. A standard deviation describes how dispersed observations are around a group mean; it is not the uncertainty interval for the mean itself. The posted comparison also reports standard errors for the means. In general, a standard error describes the sampling uncertainty of an estimate, whereas a standard deviation describes variation among observations. They answer different questions and should not be treated as interchangeable.

How should the p-value be read?

The primary comparison has an unadjusted p-value of <0.001. In general, a p-value assesses how compatible the observed data are with a specified null model, under the assumptions used for the test. It is not the probability that the null hypothesis is true, and it does not measure the size or practical importance of a difference. The registry record does not report the full analysis specification behind this p-value. The comparison is therefore best read alongside the estimate and confidence interval, rather than by using the p-value alone.

The word unadjusted matters because several outcomes and time points are posted. In general, making multiple statistical comparisons can increase the chance of seeing one or more apparently strong results by chance if every test is interpreted independently. The registry record does not report a multiplicity adjustment or a prespecified testing sequence. The primary endpoint is distinguished from secondary outcomes in the record, but the status of each secondary comparison within a formal testing plan is not reported.

What does the confidence interval add?

The primary 95% confidence interval runs from 1.567 to 3.653 for the mean difference. In general, a confidence interval gives a range of values compatible with the observed data under the analysis assumptions and communicates precision more directly than a p-value alone. A narrower interval indicates greater precision than a wider interval on the same scale. The interval does not describe the range of individual participants’ pain scores, and it does not include every uncertainty that could arise from missing data, study conduct, or analysis choices.

The confidence interval for the primary mean difference is entirely above zero. That is consistent with the observed group means and the reported unadjusted p-value. For the morphine-use comparisons, the intervals include zero. In general, an interval that includes zero is compatible with no average difference as well as values on either side of zero, at the confidence level represented by that interval. It is not proof that the groups are identical.

Why can group sizes and spread affect precision?

In general, the uncertainty of a group comparison depends partly on the amount of information in each group and the variability of the measured outcome. Smaller groups and greater spread tend to make estimates less precise, although precision also depends on the analysis and data structure. Here, the primary outcome counts are 19 and 35, and the reported standard deviations differ between the groups. The registry does not report why the outcome counts are unequal or how any missing observations were addressed.

The continuous-outcome summaries support a comparison of averages, but they do not establish that the assumptions of any particular model were met. The registry record does not report diagnostic checks, transformations, adjusted analyses, or a detailed statistical analysis plan. No reported secondary analysis entries are listed in the registry record. The presented comparisons should therefore be understood as the posted summaries and their accompanying calculations, not as a complete account of all analytical decisions.

The sample-size section uses a normal approximation and equal allocation as planning assumptions for its illustrations. Those illustrations are separate from the observed outcome summaries and do not indicate how much power the completed trial had. In general, planned power concerns the chance of detecting an effect of a chosen size under stated assumptions; it is not a measure of whether an observed result is true. The registry’s own design rationale is separately described in the trial summary.

11. Confidence Intervals and Precision

The primary mean difference is 2.61 points, with a 95% confidence interval from 1.567 to 3.653. Because the interval is above zero, the posted estimate is consistent with a higher average score in the pain-pump group, using the stated direction of subtraction. The interval gives a range of values compatible with the data under the analysis assumptions; it does not mean that 95% of individual participant differences fall within those bounds.

In general, confidence intervals communicate precision by showing how much uncertainty surrounds an estimate. A narrow interval is more precise than a wide interval for the same outcome and scale. The primary interval excludes zero, but uncertainty remains about the exact size of the group-average difference. The record does not report a threshold that would identify what size of difference is important to participants, so the interval alone cannot establish practical importance.

Precision should also be considered in light of the outcome counts: 19 in the Exparel group and 35 in the pain-pump group. The record does not explain why the posted numbers are smaller than the overall enrollment of 102, or why they differ by group. Without participant flow and missing-data details, it is difficult to assess how those counts may affect interpretation of the interval.

The secondary morphine-use intervals are wider in relation to their estimates and include zero. In general, such intervals leave room for multiple possible average differences, including no difference, rather than identifying a precise direction and size. This is a statement about the information in the posted comparisons, not proof that the underlying groups are identical. The endpoint-specific intervals in the tables and plot are the most direct way to compare the precision of the reported estimates.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The sample-size table and curve are planning illustrations based on the observed effect, not a report of the trial’s achieved power. The figures are participants per arm for 80% power and participants per arm for 90% power; they are not total event counts. The assumptions listed for these illustrations are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each row uses the stated fraction of the observed effect as the effect to detect.

The 80% power column gives the planned number of participants per arm under which the calculation would have an 80% chance of detecting the specified effect, if the planning assumptions hold. The 90% column describes the corresponding calculation for a 90% chance. These are design calculations, not guarantees about the result of a future or completed study. In the table, the rows show planning for 100%, 75%, and 50% of the observed effect. Smaller effects require more participants under these assumptions, because they are harder to distinguish from sampling variation.

The registry summary also gives the trial’s stated original sample-size rationale: a prior mean worst pain score of 5.4, a targeted change of 2 points, alpha of 0.05, beta of 0.80, 51 subjects in each group, and planned enrollment of 60 in each arm to account for drop-outs. That rationale is distinct from the posted planning illustration, which is calculated from the observed effect. The registry does not report further detail about the original calculation or whether its assumptions were updated.

The outcome counts shown in the results are 19 and 35, while total enrollment is 102. The planning figures should not be interpreted as observed power, nor as evidence that a particular number of participants would reproduce the observed result. They illustrate how required group size changes with the assumed effect size under the stated planning assumptions.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 2.610; pooled standard deviation σ = 2.382.
2. n = 2 × (1.96 + 0.842)² × 2.382² / 2.610² = 13.1, rounded up to 14 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 2.61                      # observed difference in means
sigma <- 2.38199415487237                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(4364867)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 14 (80% power), 18 (90% power)
 75% of observed effect: n per arm = 24 (80% power), 32 (90% power)
 50% of observed effect: n per arm = 53 (80% power), 71 (90% power)
power.t.test: 14.1 
Simulated power at n = 14 per arm: 0.795 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry record identifies pain score in the 24 hours after surgery as the primary endpoint and lists several secondary outcomes, including later pain scores and cumulative morphine milligram equivalents. It does not report how the possibility of multiple comparisons was handled. There is no reported adjustment method, testing hierarchy, or statement identifying which secondary comparisons were intended to support formal confirmatory conclusions. The p-values attached to the posted comparisons are unadjusted.

In general, multiplicity matters when several hypotheses are tested: interpreting every result with the same threshold can make chance findings more likely across the collection of tests. One approach is to define a testing sequence or adjust the analysis; another is to treat secondary results as exploratory. The record does not say which approach the investigators planned. The primary result remains the designated main endpoint, while secondary results should be interpreted with this uncertainty about the analysis plan in mind.

Missing-data information is also limited. The overall enrollment is 102, but the posted primary and secondary outcome summaries show 19 participants in the Exparel group and 35 in the pain-pump group. Reasons for the difference between those counts and total enrollment are not reported in the registry record. The record does not describe withdrawals, exclusions, completion of follow-up, or how missing outcome values were handled.

The analysis population is not described. In particular, the registry record does not say whether the comparisons used all randomized participants, only participants with recorded outcomes, or another population. It also does not report whether participants were analyzed according to their assigned group or whether any adjusted analysis was performed. These omissions prevent a full assessment of how missing outcomes or post-randomization events could affect the estimates.

There are no reported analysis entries for the secondary outcomes in the registry record. The posted outcome summaries and comparisons can still be read as reported data, but the record does not supply enough detail to reconstruct the complete analysis process. These limitations affect confidence in the scope and robustness of the inferential claims; they do not, on their own, identify the direction or size of any bias.

15. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: catheter dislodgement (5.7%).

The registry reports serious adverse events for 19 participants at risk in the Exparel group and 35 in the pain-pump group. No serious adverse events were reported in the Exparel group, compared with 2 affected participants in the pain-pump group. The record reports no deaths in either group. Other, non-serious adverse events were reported for 0 of 19 participants in the Exparel group and 0 of 35 in the pain-pump group.

These counts are descriptive. They show the numbers recorded in each group, but they do not by themselves establish whether a treatment caused an event or whether an apparent difference is reliable. The groups are of different sizes, and the number of serious events is small. The registry lists Catheter Dislodgement at 5.7% among the top serious terms; further context about the event and its attribution is not reported in the registry record.

The safety figures should be read as a summary of events recorded in this trial, not as a complete account of all possible harms or a comparison adjusted for differences in follow-up or participant characteristics. The registry record does not report additional event-level detail, severity grading beyond the serious-event classification, or a statistical comparison of adverse events.

16. What the Result Does, and Does Not, Mean

The posted results show that, among participants with recorded primary outcomes, the average worst pain score during the first 24 hours after surgery was lower in the Exparel group than in the pain-pump group. The estimated difference was 2.61 points in the direction pain pump minus Exparel, and the 95% confidence interval was from 1.567 to 3.653. This describes the reported group averages and the precision of that comparison.

The result does not show that every participant in the Exparel group had a lower score, nor does it describe the individual experience of any particular participant. A mean difference summarizes the groups, while individual scores may vary. The record does not provide the score distributions or participant-level data needed to examine that variation in detail.

The result also does not by itself establish why the group averages differ, how important the difference is to participants, or whether it applies beyond the trial population. The registry does not report a threshold for a meaningful score difference, and the posted primary outcome counts are smaller than total enrollment. Reasons for the outcome counts and details about missing data are not reported in the registry record.

The trial’s results do not answer all of the objectives described in its summary. Pain scores at later times and some morphine-use outcomes are posted, but return of functional use of the arm and cost savings are not reported in the registry record. The secondary comparisons are unadjusted, and the registry does not report how multiple testing was addressed. Those details call for caution when considering the secondary pattern alongside the primary estimate.

In general, a trial result is one piece of evidence whose interpretation depends on its design, measured outcomes, completeness of data, and analysis. Here, randomization is reported, but details of the randomization process, masking, participant flow, missing-data handling, and analysis population are limited or not reported. The posted comparisons should therefore be understood within the information available in the registry record, not as a complete account of every design and analysis decision.

17. Why This Trial Matters Statistically

This trial is statistically informative because it reports a continuous primary outcome with group means, standard deviations, a mean difference, a confidence interval, and an unadjusted p-value. These complementary summaries show both the direction and estimated size of the group-average comparison and the uncertainty around it. Reading them together is more informative than relying on a significance label alone.

It also illustrates why the outcome count matters when interpreting a completed randomized trial. The registry lists enrollment of 102, while the primary outcome summaries include 19 participants in one group and 35 in the other. Without a participant flow account or a description of missing data, readers cannot determine from the registry alone why these counts differ. Statistical precision is visible in the interval, but the relationship between the analyzed outcomes and all enrolled participants remains unclear.

The trial distinguishes a primary endpoint from several secondary measures. That structure gives the main pain comparison a clear role, while the later pain and morphine-use results provide context. However, when multiple outcomes are reported without a stated adjustment or testing hierarchy, secondary p-values should be interpreted cautiously. The record’s lack of detail about multiplicity is therefore relevant to how much weight readers place on patterns across outcomes.

Finally, the sample-size illustrations show how planning depends on the effect one aims to detect, and how smaller assumed effects require more participants under the stated assumptions. They are separate from the original trial rationale and from the observed outcome counts. Keeping those distinctions clear helps avoid confusing a planning calculation with evidence about the completed trial.

18. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

Several limitations are specific to what is visible in this trial record. Although the study is marked randomized, details of sequence generation and allocation concealment are not reported. The trial is listed as having no masking, so the record does not describe blinding of participants or study personnel. The registry does not report how these features were considered in the analysis or interpretation.

The gap between total enrollment of 102 and the primary outcome counts of 19 and 35 is not explained. Participant flow, reasons for missing outcomes, withdrawals, and exclusions are not reported in the registry record. The analysis population and missing-data method are also not reported, limiting assessment of whether the estimates represent all randomized participants.

The posted outcome set is incomplete relative to the objectives in the study summary. The record describes objectives involving functional use of the arm and cost savings, but results for those outcomes are not reported. It lists morphine use at 72 hours as a secondary outcome, but the posted secondary results do not include that comparison. Thus, the registry record does not permit a complete assessment of all stated objectives.

The analysis plan is not described in enough detail to establish how multiple testing was handled, whether outcomes were selected or prioritized before data review, or what model assumptions were assessed. Secondary p-values are unadjusted, and no secondary analysis entries are listed. Additional details about data collection for the pain scale, follow-up completeness, and event attribution are not reported. These are limits of the record’s transparency; they do not establish that a particular analysis choice was made or that the results are biased.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Exparel for Total Shoulder Arthroplasty — NCT04364867.
• Registry record last updated 2024-11-26; status last verified 2022-06.
• Results first posted 2024-11-26.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

22. Record Summary

The registry record describes a completed, randomized, unmasked, parallel-group Phase 4 trial of Exparel versus a pain pump after total shoulder arthroplasty. It lists total enrollment of 102 and identifies worst pain score during the 24 hours after surgery as the primary endpoint. The posted primary results include 19 participants in the Exparel group and 35 in the pain-pump group.

The primary mean scores were 0.76 and 3.37, respectively, with a reported mean difference of 2.61 for pain pump minus Exparel. The 95% confidence interval was 1.567 to 3.653, and the unadjusted p-value was <0.001. Secondary results include later pain scores and morphine-use measures, but the registry does not report results for all objectives described in the summary.

Important details about participant flow, missing data, analysis populations, and multiplicity are not reported in the registry record. The results should be read as posted group summaries with those limitations in view.